[Two types of magnetic biological effects: individual and batch effects].

Frequency distributions of the magnetic effects values have been calculated based on the results of about 120 thousand single trials during psychophysical testing of 40 people under normal conditions and exposure to the hundredfold weakened geomagnetic field. Two types of such distributions were shown to be attributed to a) the individual reactions to the change of a magnetic field and b) the batch magnetic effect on the set of the individual reactions. The methodological consequences significant for detecting magnetic biological phenomena and studying their nature are discussed.